Mathematical Simulation of Acoustic Characteristics of Super-Power Arc Discharges in Electric Steel Furnaces

2015 ◽  
Vol 792 ◽  
pp. 499-504
Author(s):  
Roman Bikeev ◽  
Viktor Serikov ◽  
Vladimir Cherednichenko
Keyword(s):  
Arc Discharge ◽  
Low Frequency ◽  
Sound Intensity ◽  
Electric Arc ◽  
Intensity Level ◽  
Discharge Column ◽  
Saha Equation ◽  
Electromechanical Oscillations ◽  
Noise Characteristics ◽  
Arc Discharges

Mathematical model of appearance and progress of noise characteristics in super-power electric arc steel furnaces is considered in the paper. It is shown that noise generation is coupled with pulsations of axial plasma flows in arc discharge caused by fluctuations of electrodynamic pressure on discharge column formed by interaction between its own magnetic field and current flowing in the arc. Simulation results have shown that pressure in arc axis alternates at frequency 100 Hz with amplitude 6600 N/m2 for arc current 80 kA. Basic frequencies of arc noise are aliquot to 100 Hz, that fact is verified by exploitation practice of arc steel furnaces. Sound intensity level in workspace riches 160 dB, but thanks to shielding by case and fused metal and slag it falls to 115–120 dB on service area of furnace. It has shown that maximal amplitudes in frequency spectrum of the noise are in range 5–150 Hz. Generated noise amplitudes and frequency ranges depend on arc discharges' resistance, which are defined by ionization level of gases. According to Saha equation, iron vapor is ionized by 70 %, calcium vapor – by 95 %, and ionization level of air is no more than 1.5 %. It has been experimentally shown that in melting of stock coated with lime noise intensity is decreased by 6–8 % against no-lime iron melting because of lower calcium ionization potential (6.11 eV). It has been ascertained that for long arc with high voltages the sound intensity is decreased by 3–4 % as compared with short arc of the same current. It has shown that suppression of low-frequency components of noise energy is possible by optimization of electromechanical oscillations of electrodes, electrode-holders and cable strips, additionally to inclusion lime in stock mixture. The appropriateness of improvement electric arc furnaces hermeticity and development of the furnaces for operation with lowered currents and enlarged transformers' voltages have been approved.

scholarly journals COMPOSITE Cu-Cr MATERIALS UNDER THERMAL ACTION OF ELECTRIC ARC DISCHARGE PLASMA

2021 ◽  
pp. 98-101
Author(s):  
A. Murmantsev ◽  
A. Veklich ◽  
V. Boretskij ◽  
M. Bartlová ◽  
L. Dostál ◽  
...  
Keyword(s):  
Discharge Plasma ◽  
Arc Discharge ◽  
Plasma Temperature ◽  
Thermal Action ◽  
Optical Emission ◽  
Electric Arc ◽  
Composite Electrodes ◽  
Plasma Parameters ◽  
Arc Discharges ◽  
The Impact

The results of optical emission spectroscopy (OES) investigation of plasma of electric arc discharges in steadystate mode between Cu-Cr composite electrodes, manufactured at different sintered temperatures: 750, 850, 950 or 1050 °C, is presented. In particular, the impact of sintering temperature on erosion resistanceof such composite materials, which was determined in indirect manner by estimation of metal vapours content in the midsection of discharge gaps, is studied by the analysis of plasma parameters. These contents were calculated in assumption of local thermodynamic equilibrium (LTE) on the base of experimentally obtained radial distributions of plasma temperature and electron density.

scholarly journals Carbon Nanofoam by Pulsed Electric Arc Discharges

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
David Saucedo-Jimenez ◽  
Isaac Medina-Sanchez ◽  
Carlos Couder Castañeda
Keyword(s):  
Carbon Nanostructures ◽  
Arc Discharge ◽  
Low Cost ◽  
Molar Fraction ◽  
Electric Arc ◽  
Graphite Electrodes ◽  
Electric Arc Discharge ◽  
Pure Carbon ◽  
Arc Discharges ◽  
Dc Current

The aim of this article was to report the carbon nanofoam synthesis by a new method and a new catalytic mixture. Using the pulsed electric arc discharge method, carbon nanofoam was synthesized. The synthesis was carried out in a controlled atmosphere at 200 torr of hydrogen pressure. The pulsed electric arc discharge was established between two graphite electrodes with 22.8 kVA of power and 150 A DC current; the cathode was relatively motionless and was made of a pure carbon rod of 6 mm diameter, and the spinner anode was a pure carbon disc spinning at 600 rpm; over the disc was an annular cavity where the new catalytic mixture of 93.84/2.56/1.43/0.69/1.48 of C/Ni/Fe/Co/S molar fraction was deposited in a geometrically fixed way by 8 catalytic mixture blocks and 8 empty spaces, and the discharge frequency was 80 Hz. After the synthesis was made, the resulting products were deposited on the electrodes, proving that our method can synthesize different carbon nanostructures easily and at low cost.

scholarly journals Effect of intensity and duration of anthropic noises on European mink locomotor activity and faecal cortisol metabolite levels

2022 ◽  
Author(s):  
Lorena Ortiz-Jiménez ◽  
Carlos Iglesias-Merchan ◽  
Alba Itzel Martínez-Salazar ◽  
Isabel Barja
Keyword(s):  
Locomotor Activity ◽  
Noise Exposure ◽  
Sound Intensity ◽  
Exposure Level ◽  
Intensity Level ◽  
Road Noise ◽  
Noise Emission ◽  
European Mink ◽  
Noise Characteristics ◽  
Activity Duration

Abstract Human activities involving noise emission can affect wild animals. European mink was exposed to road noise and human voice playbacks to analyse how sound intensity level and duration of both noises altered the time that individuals were active and if their faecal cortisol metabolite (FCM) levels varied. A Hierarchical Analysis Cluster was performed to established two mink groups with respect to both noise source type: short duration/low intensity (SL) and long duration/high intensity (LH). We performed General Linear Mixed Models to evaluate the variation in locomotor activity duration (s) and FCM (ng/g) levels, respectively. The results showed both road noise and human voices decreased locomotor activity duration in SL more sharply compared to LH, and human voices were the triggers that induced the most pronounced response to both exposure conditions. FCM levels increased in SL compared to LH during road noise while the opposite happened during human voices. Differences based on sex and age of individuals were observed. In conclusion, noise characteristics given by the sound type determined the variations in locomotor activity duration while noise exposure level determined the variations in FCM levels. Attention should be paid to noisy activities (e.g. recreational activities for visitors in protected natural areas) and loud groups of people to conserve wildlife, especially noise sensitive species.

scholarly journals Plasma Peculiarities of Arc Discharge Between Carbon-Copper Electrodes

2019 ◽  
Vol 6 (2) ◽  
pp. 152-155
Author(s):  
A. Veklich ◽  
S. Fesenko ◽  
V. Boretskij
Keyword(s):  
High Speed ◽  
Arc Discharge ◽  
Electric Arc ◽  
Arc Plasma ◽  
Composite Electrodes ◽  
Plasma Properties ◽  
Mutual Correlation ◽  
Copper Electrodes ◽  
Arc Discharges ◽  
Discharge Gap

Composite materials on carbon-copper base have advanced electric and exploitation characteristics. They usually used as materials for sliding contacts for high-speed railway. Arc discharges appear during pantograph lowering process in pantograph-catenary system, so injection of contact material into discharge gap has place. Therefore, investigations of electric arc plasma between such composite electrodes can be useful for further optimization of materials. It would be very useful as well to examine the peculiarities of electric arc plasma and contacts’ working surface interaction. So, the aim of this work is spectroscopy investigations of electric arc discharge plasma between C-Cu composite electrodes. The mutual correlation of plasma properties and composition of contacts’ was found.

scholarly journals PLASMA-SURFACE INTERACTION OF ELECTRIC ARC DISCHARGE BETWEEN COMPOSITE Cu-Cr ELECTRODES

2020 ◽  
pp. 174-178
Author(s):  
A. Murmantsev ◽  
A. Veklich ◽  
V. Boretskij ◽  
M. Bartlová ◽  
L. Dostál ◽  
...  
Keyword(s):  
Arc Discharge ◽  
Optical Emission ◽  
Electric Arc ◽  
Surface Interaction ◽  
Composite Electrodes ◽  
Plasma Parameters ◽  
Plasma Surface ◽  
Air Atmosphere ◽  
Different Temperatures ◽  
Arc Discharges

In this work the plasma of electric arc discharges between Cu-Cr composite electrodes, which material were pressured and sintered at different temperatures 750 or 1050°С, are investigated by Optical Emission Spectroscopy (OES). The Scanning Electron Microscopy (SEM) with Energy-Dispersive X-ray Spectroscopy (EDXS) are used to study the working surface of electrodes, modified by thermal effect of breaking electrical arc in the air atmosphere. The erosion intensity of electrodes’ material due to plasma-surface interaction is estimated in indirect way by determination of metal vapours content in the discharge gap in an assumption of local thermodynamic equilibrium (LTE). The plasma composition is calculated in this case on the base of experimentally determined plasma parameters: temperature and electron density.

Investigation of Low-Frequency Noise Characteristics in Gated Schottky Diodes

2021 ◽  
Vol 42 (3) ◽  
pp. 442-445
Author(s):  
Dongseok Kwon ◽  
Wonjun Shin ◽  
Jong-Ho Bae ◽  
Suhwan Lim ◽  
Byung-Gook Park ◽  
...  
Keyword(s):  
Schottky Diodes ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Noise Characteristics

Microfabricated Fiber Probe by Combination of Electric Arc Discharge and Chemical Etching Techniques

2012 ◽  
Vol 462 ◽  
pp. 38-41 ◽  
Author(s):  
Wan Maisarah Mukhtar ◽  
P. Susthitha Menon ◽  
Sahbudin Shaari
Keyword(s):  
Optical Fibers ◽  
Chemical Etching ◽  
Arc Discharge ◽  
Etching Rate ◽  
Electric Arc ◽  
Buffer Solution ◽  
Fiber Probe ◽  
Optical Fiber Probes ◽  
Electric Arc Discharge ◽  
Fiber Probes

In this study, optical fiber probes were fabricated by combination of electric arc discharge and chemical etching techniques. Size of tips diameters fabricated using different etching solutions were observed. When the optical fibers were pulled and heated by the electric arc discharge using a fusion splicer, fiber tips with few microns in diameter were obtained. To minimize the tips diameter, the pulled fiber probes were etched vertically for 10 minutes using two different etching solutions namely 49% HF and HF buffer solution (49% HF and 40% NH4F) with ratio of 2:1. A thick overlayer was added on top of the HF solution to prevent dangerous vapors escape to the environment. When the tapered part of the pulled fiber (FP1) was dipped into 49% HF solution, the diameter of tip was slightly decreased from 4.41μm to 1.31μm with etching rate of 5.17x10-3 μms-1. When the pulled fiber (FP2) was etched into HF buffer solution, the etching rate was increased up to 52.35% with the etching rate of 10.85x10-3μms-1. The tip diameter was reduced from 7.01μm to 468.9 nm in diameter. Combination of “heat and pull” technique with chemical etching by using HF buffer solution produced fiber probe with small tip diameter.

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